Railway traffic controlling apparatus



R. M GILSON ET AL RAIL-WAY TRAFFIC CONTROLLING APPARATUS Oct. 18, 1932..

Filed June 9, 1952 v INVENTORS 52 RoberzM. 0518012 and BemzamiEOZlayazz fismf" mm: ATTORNEY.

W M f m 2 H I. 2 W "a w Q m w Patented Oct. 18,1932

UNITED STATES PATENT; OFFICE.

ROBERT M. crILsoN, or PITTSBURGH, Ann BERNARD n. OHAGAN, o swIssvALE, PENN.- sYLvAN A, ASSIGNOBS To THE UNION SWITCH & SIGNAL COMPANY, onswrssvann,

PENNSYLVANIA, A GORIPORATIQN or PENNSYLVANIA RAILWAY TRAFFIC CONTROLLING APPARATUS Application filed June 9,

Our invention relates to railway traffic controlling apparatus, and particularly to apparatus for the protection of a railway switch motor against. overload. r We will describe two forms of'apparatus embodying our invention, and will then point out the novel features thereof in claims.

Fig. 1 of the accompanying drawing is a T diagrammatic view showing oneform of apparatus embodying our invention. 7 Fig. 2 is a modification of the apparatus shown in Fig. 1, and also embodying our invention."

Similar reference characters refer to similar parts in each-of the two figures.

Referring to Fig. 1 of the drawing, the reference character 8 designates a railway switch which is actuated by an electric motor M' having an armature 1 and afield 2. Operatively connected with the switch is a cut-out i controller D comprisinga contact arm 3 and contacts 4. and 5. Contact 8+4 isclosed at all times except when the switch occupies its extreme reverse position, and contact 3-5 is closed at all times except when the switch occupies its extreme normal position.

The motor M is controlled by a two-element alternating current relay E having a constantly energized local winding 6, and a control winding '4' which is energized with ourrent of one or the-other instantaneous polarity according as the pole-changer, P occupies one or the other position. Reversing polechanger P reverses the instantaneous polarity of the current supplied to control winding? and causes polar contacts 8, 9'and 10 ofrelay ciently long so that relay A will not close its front contact 25 uponmomentary surges of -motorcurr.ent such as occur at starting. The reason for making resistor Rof-positive ,tem-

1932. Serial No. 616,184;

perature coefficient material isto provide an inverse time element in the operation ofrelay A as an aid in preventing the pickup. of this relayron surges of current which are high in value but of relatively short duration, such as starting and reversal surges, as well as to provide a wider margin of operation of relay A when used with motorsin which the overload current may vary over an appreciably wide range.

' The reference character B designates an alternating current relay having a pick-up 011'011113'60111310116d by contact 25 ofrelay A and capable of interrupting the motor circuit at back contact 1920. A holding circuit for relay B becomesclosed over front contact 32-33, and remains closed thereafter until relay E is pole-changed. The release period of relay B is so adjusted that this relay-will release during the open circuit interval which occurs when contact 10 of relay E is being reversed. l 1 As shown in the drawing, the switch S occupies its normal position and controller D as well as pole-changer P also occupy the normal position, relays A and B being deenergized. p

When the switchis to be moved to the reverse'position, the operator, will reverse polechang'er P, thereby reversing contacts 8, 9 and 10 of relay'E. The circuit for motor M i can now be traced from one terminal BX of a source, wires 11 and12, contact 9 of relay E, wire 13, armature 10f motor M, wire 14, contact 8 of relay E, wire 15, contact 3-4 ofcontroller D, wire 16, field winding-2 .of motor M, wire 17, resistor R, wire 18, back contact 1920 of relay B, and wire 21, to

the other terminal CX of the source. Motor M will now move switch S to the reverse position. V f r When the switch is tobe restored to the normal position from the reverse, polechanger P and therefore contacts 8, 9 and 10 or relay E will be restored to the position shown in the drawing. The circuitfor motor .M will now extend from 'one'terminal BX,

wire '23,, contact 80f relay E, wire 14, armature 10f motor M, wire 13,- contact 9 of relay E, wire'24, contact 3+5 of controller 1).

H. Le

switch is being moved to the reverse position,

the pickup circuit for relay B may be traced from one treminal BX, wire 11, contact 10 of relay E, wires 30 and 27, winding of relay B, wire 28, front contact 25 of relay 4, andwires 29 and 21 to terminal CX. Re-

lay B will now pick up, interrupting the mo" tor circuit at back contact 1920 and closing its own holding circuit at front contact 32,33. Relay B will continue to remain energized, keeping the motor circuit open, until pole-changer P is reversed to reverse contact 10 of relay E. Since contact 10 is includedin the holding circuit for relay B, this operation will deenergize relay B, causing the motor circuit to become re-closed preparatory to the subsequent reversal of the switch.

The cooling time of resistor R is made sufficiently short to permit quick release of relay A so that a reversal of switch S may be made immediately following the occurrence of an overload. It will be apparent that relay A could be replaced by a slow pick-up alternating current relay, thus eliminating rectifier Q. It will also be apparent that the apparatus of Fig 1 can be applied to the control of a direct current motor by substituting direct current apparatus for relays E and B, and eliminating rectifier Q.

Referring now to Fig. 2, the apparatus shown therein is similar to that disclosed in Fig. 1 with the exception that the switch S is controlled by a direct current motor, supplied with energy from a rectifier '1.

Assuming that pole-changer P of Fig. 2 is reversed, motor M will operate switch S to the reverse position over a circuit which e1:-

tends from one terminal BX, resistor R,

' vire 34, contact 35 of relay E, wire 36, contact 34 of controller D, wires 37 and 38, rectifier T, wires 39 and 40, contact 41 of relay E, wire 42, armature 1 of motor M, wire 43, contact 44 of relay E, wires 45 and 46, field winding 2 of motor M,wire 47, rectifier T, wire 48, back contact 1920 of relay B, and wires 49 and 50 to terminal (3X.

To restore switch S to the normal position, pole-changer P will be restored to the position illustrated, whereupon a reverse operat ing circuit for motor M will become closed. This circuit may be traced from one terminal BX, resistor R, wire 34, contact-35 of relay E, wire 51, contact 35 of controller D, wires 87 and 38, rectifier T, wires 39 and 52, contact 44'of relay E, wire 43, armature 1 of motor M, wire 42, contact 41 of relay E, wire 46, field winding 2 of motor M, wire 47, rectifier T, wire 48, back contact 19-20 of relay B, and wires 49 and 50 to terminal C-X.

The manner in which the apparatus of Fig. 2 operates when an' -overload occurs on motor M is identical with that described in connection with Fig. 1, so that no additional claims without departing from the spirit and scope of'our invention.

Having thus described our invention, what we claim is: i

1. In combination, an electric motor, a circuit for operating said motor, a manually controlled device for supplying current to said circuit, a resist-or having a positive temperature coefficient mcluded 1n said motor circuit, a first relay responsive to the potentlal across sald resistor 1n such manner that said first relay becomes energizedwhen the current carried by said resistor exceeds a predetermined value, a second relay, means controlled by said first relay for energizing said second relay whensaid firstrelay isen- 5 ergized, means controlled by said second relay for interrupting said motor circuit when said second relay is energized, a holding circuit for said second relay, and means controlled by said device for at times rendering said holding circuit ineffective. v V

2. In combination, an electric motor, acircuit for operating said motor, a manually controlled device for supplying current to said circuit, a resistor-having a positive temperature ccefiicient included in said motor circuit, a slow-acting relay connected across said resistor which relay becomespicked up when the current carried by said resistorexceeds a predetermined value, a second relay, means controlled by saidslow-actmg relay for energizing said second relay when said slow-acting relay is picked up, means controlled by said second relay for interrupting said motor. circuit when said second relay is energized,pand a holding circuit for said sec ond relay governed by said manuallycontrolled device. r

3. In combination, an electric motor, a cir cuit for operating said motor, a manually controlled pole-changer for reversibly supplying current to said motor circuit, a resistor having a positive temperature coeflicient included in said motor circuit, a cilfcuit breaker for said motor, means responsive to the potential across said resistor when the current carried thereby exceeds a predetermined value for closing an energizing circuit for said circuit breaker, a holding circult for said circuit breaker efiective when said clrcult breaker has become energized,

' means controlled by said circuit breaker for interrupting said motor circuit when said clrcult breaker becomes energlzed, and means i controlled by said pole-changer efi'ective during a reversal of said pole-changer for interrupting said holding circuit.

4. In combination, an electric motor, a circuit for operating said motor, a manually controlled pole-changer having a normal and a reverse position for reversibly supplying current to said motor circuit, a resistor having a positive temperature coeflicient included in said motor circuit, a first relay connected across said resistor which becomes picked up when the current carried by said resistor exceeds a predetermined value, a second relay,

having a release time interval sufficiently short to permit release during a reversal of said pole-changer, a pick-up circuit for said second relay effective when said first relay is picked up, means controlled by said second relay forrenderingsaidmotorcircuitinefi'ective when said second relay is picked up, a holding circuit for said second relay efi'ective when said second relay is picked up and said polechanger occupies said normal or said reverse position, and means controlled by said polehanger effective for interrupting said holding circuit while said pole-changer is'being reversed.

5. In combination, a reversible direct current motor, an alternating current source of supply, a rectifier connected between said motor and said source, a resistor having a positive temperature coeflicient connected between said rectifier and said source, a manually controlled pole-changer for reversing the direction of current flow to said motor, a first relay connected across said resistor which becomes picked up when the current carried by said resistor exceeds a predetermined value, a second relay having a pick-up circuit which becomes closed when said first relay is picked up, a holding circuit for said second relay efiective when said second relay is picked up, means effective for interrupting the supply of current to said rectifier when said second relay is picked up, and means controlled by said pole-changer for interrupting said holding circuit. 7

In testimony whereof we aifix our signatures.

ROBERT M. GILSON. BERNARD E. OI-IAGAN. 

